scholarly journals Numerical Modeling of Square Steel Members Wrapped by CFRP Composites

2019 ◽  
Vol 8 (10) ◽  
pp. 3082-3087 ◽  
Keyword(s):  
Failure Modes ◽  
Ultimate Load ◽  
Local Buckling ◽  
Axial Loading ◽  
Test Results ◽  
Structural Members ◽  
Cfrp Sheets ◽  
Tubular Columns ◽  
Steel Members ◽  
Strain Behaviour

HSS (Hollow Structural Steel) tubular members used in buildings and bridges for structural application is rapidly developing technique in the recent era. Since, they have many advantages over RC structural members. This paper presents the application of CFRP on HSS tubular members under axial compression. Typical failure occurred during axial loading was local buckling, and this could be reduced by wrapping CFRP sheets around the HSS tubular columns were investigated experimentally. Eight steel samples are used in this test. Among eight specimens, two are unwrapped and the remaining six columns are externally wrapped by CFRP. CFRP sheets are used as strips, and the width of the sheets are constant. The spacing between the CFRP sheets is also constant. All columns are tested in column tester till the maximum to understand their failure modes, Ultimate load, load Vs. Displacement, Stress- Strain behaviour and Ductility index. Finally, results obtained from the experimental investigation could be validated with ANSYS software. The ultimate load and displacements from ANSYS validation are closely match with test results.

scholarly journals Axial Loading Behaviour of Self-Compacting Concrete-Filled Thin-Walled Steel Tubular Stub Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yunyang Wang ◽  
Lei Xiao ◽  
Chu Jiang ◽  
Yandong Jia ◽  
Guang Yang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Ultimate Load ◽  
Local Buckling ◽  
Axial Loading ◽  
Steel Tube ◽  
Self Compacting Concrete ◽  
Steel Tubes ◽  
Thin Walled ◽  
Stub Columns ◽  
Versus Strain

This paper presents an experimental investigation on the mechanical behaviour of self-compacting concrete-filled thin-walled steel tubular (SCCFTST) stub columns loaded in axial compression to failure. Four specimens were tested to study the effect of diameter to wall thickness (D/t) ratios on the ultimate load, failure modes, and ductility of the columns. Confinement of the steel tube to concrete was also addressed. The failure modes, load versus displacement curves, and load versus strain curves were examined in detail. The experimental results showed that the ultimate state is reached when severe local buckling and rupture occurred on the steel tubes, and the concrete near the rupture has been crushed. The columns with larger D/t ratios appeared more local buckling, and its location is more close to the end of the columns. The SCCFTST stub columns with smaller D/t ratios show higher ultimate load and better ductility, and the steel tubes can exert higher confinement to the concrete.

scholarly journals Compression Test on Cold-Formed Steel Built-Up Back-to-Back Channels Stub Columns

2011 ◽  
Vol 201-203 ◽  
pp. 2900-2903 ◽  
Author(s):  
Chui Huon Tina Ting ◽  
Hieng Ho Lau
Keyword(s):  
Compression Test ◽  
Failure Modes ◽  
Local Buckling ◽  
Effective Width ◽  
Test Results ◽  
Direct Strength Method ◽  
Cold Formed Steel ◽  
Stub Column ◽  
Hot Rolled ◽  
Stub Columns

Built-up sections are used to resist load induced in a structure when a single section is not sufficient to carry the design load for example roof trusses. In current North American Specification, the provision has been substantially taken from research in hot-rolled built-up members connected with bolts or welds [1]. The aim of this paper is to investigate on built-up back-to-back channels stub columns experimentally and theoretically using Effective Width Method and Direct Strength Method. Compression test was performed on 5 lipped channel and 5 back-to-back channels stub columns fabricated from cold-formed steel sheets of 1.2mm thicknesses. The test results indicated that local buckling is the dominant failure modes of stub columns. Therefore, Effective Width Method predicts the capacity of stub columns compared to Direct Strength Method. When compared to the average test results, results based on EWM are 5% higher while results based on DSM are 12% higher for stub column.

Experimental Investigation of Stiffened Square CFST Columns under Axial Load

2014 ◽  
Vol 919-921 ◽  
pp. 1794-1800
Author(s):  
Xin Zhi Zheng ◽  
Xin Hua Zheng
Keyword(s):  
Experimental Investigation ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Axial Load ◽  
Local Buckling ◽  
Test Results ◽  
Tubular Columns ◽  
Economical Benefit ◽  
Steel Consumption ◽  
Cfst Columns

Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.

Development of Splice Connections for Precast Concrete Structures

2014 ◽  
Vol 980 ◽  
pp. 132-136 ◽  
Author(s):  
Ahmad Baharuddin Abd Rahman ◽  
Jen Hua Ling ◽  
Zuhairi Abd Hamid ◽  
Mohd Hanim Osman ◽  
Shahrin Mohammad ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Failure Modes ◽  
Ultimate Load ◽  
Precast Concrete ◽  
Tensile Load ◽  
Test Results ◽  
Steel Bars ◽  
Embedment Length ◽  
Bar Diameter

This paper presents the test results of proposed grouted sleeve connections under increasing tensile load. The objective of this research was to investigate splice connections that could provide tensile strength similar to the full tensile strength of the connected rebars. The parameters varied were splice types, splice length and rebar embedment length. The performance of the splice connection was evaluated based on the load-displacement, ultimate load, displacements and failure modes. The results show that the strength of splice connection depends on the bond strength between sleeve-to-grout and grout-to-rebar; the tensile strength of spliced steel bars and also the tensile strength of sleeve. It is observed that when the grout compressive strength is more than 60N/mm2and bar embedded length is at least 10 bar diameter, the splice connection in BS series is able to provide full tensile strength of the connected rebars.

Calculating Temperature Distribution in Concrete Encased H-Section Steel Column in Fires Using TFIELD

2012 ◽  
Vol 204-208 ◽  
pp. 3445-3449
Author(s):  
Yong Jun Liu ◽  
Ran Bi ◽  
Yan Wang
Keyword(s):  
Temperature Distribution ◽  
Construction Materials ◽  
Local Buckling ◽  
Steel Structure ◽  
Structural Members ◽  
Additional Advantage ◽  
Natural Fire ◽  
Standard Fire ◽  
Steel Members ◽  
Steel Column

Steel–concrete composite columns are used extensively in modern buildings in recent decades due to the benefits of combining two construction materials: reinforced concrete is inexpensive, massive, and stiff, while steel members are strong, lightweight, and easy to assemble. For concrete-encased composite structural members, an additional advantage is that the concrete used for encasing a structural steel not only increases its stiffness, but also protects it from fire damage and local buckling failure. Traditionally, the fire resistance of composite structural members has been determined in standard fire tests, with the temperature-time curves representing more severe heating conditions compared to that which occurs in many typical natural fire compartments. To design a concrete encased H-section steel structure safely and economically, it is necessary to calculate temperature distribution in composite steel-concrete columns under natural fire. In this paper, the program TFIELD written by first author is used to calculate the temperature distribution in a concrete encased H-section steel column under natural fire and ISO 834 fire. The calculating results under the standard ISO 834 fire and a natural fire have been compared which exhibit obvious differences.

CYCLIC DAMAGE IN STEEL EXPERIENCING SEISMIC LOADING

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2478-2483 ◽  
Author(s):  
C. K. SEAL ◽  
M. A. HODGSON ◽  
W. G. FERGUSON
Keyword(s):  
Failure Modes ◽  
Strain Curve ◽  
Field Analysis ◽  
Test Results ◽  
Steel Members ◽  
Growing Crack ◽  
Load Regime ◽  
Remaining Capacity ◽  
Accumulation Of Damage ◽  
Cyclic Damage

During the mid 1990s earthquakes in Northridge, California, and Kobe, Japan, illustrated a lack of understanding of the behaviour of structural steels exposed to seismic loads. Under this type of load regime, structural steel members are subjected to fully plastic load cycles and unexpectedly brittle failures may result. A method for determining the accumulation of damage through cyclic pre-straining is proposed. Toughness, as defined by the area under the true stress strain curve, is used as an indicator of the level of damage that the steel has suffered and from this some idea of its remaining capacity to further deform can be determined. Observations during the testing of these samples have indicated that there is a transition in the failure mode from a fatigue type failure, with a progressively growing crack, to an overload failure, in which the steel fails due to a lack of ability to further deform. Similar transitions have been noted by other researchers in the field. Analysis of the test results seems to show differences in the damage accumulation behaviour that may be used to identify when this transition in failure modes may occur.

Overlapped K Joints in Circular Hollow Sections Under Axial Loading (An Investigation of the Factors Affecting the Static Strength Using Numerical Modeling)

1996 ◽  
Vol 118 (1) ◽  
pp. 53-61 ◽  
Author(s):  
E. M. Dexter ◽  
M. M. K. Lee ◽  
M. G. Kirkwood
Keyword(s):  
Failure Modes ◽  
Load Transfer ◽  
Numerical Models ◽  
Axial Loading ◽  
Static Strength ◽  
Test Results ◽  
Factors Affecting ◽  
Current Design ◽  
The Relationship ◽  
Design Guidance

Overlapped joints are generally regarded as having higher strengths than otherwise identical, simple nonoverlapping joints because of the more efficient load transfer between braces. However, not only that relatively little research has been carried out on such joints, the few test data from which current design guidance was derived has also been recently rejected. This paper reports the first phase of a parametric finite element study into the strength of overlapping K joints under axial loading. The numerical models were validated and calibrated against existing gap and overlapped K joint test results, and various factors which affect the relationship between the strength and the overlap amount, such as boundary restraints, hidden welds, loading hierarchy, and failure modes, were investigated. The results of the work presented lay the foundation for a future parametric study.

Damage assessment of steel angle members subjected to very-low-cycle loading

2006 ◽  
Vol 33 (10) ◽  
pp. 1293-1303
Author(s):  
Yeon-Soo Park ◽  
Sun-Joon Park ◽  
Sung-Hoo Kang ◽  
Byung-Chul Suh
Keyword(s):  
Damage Assessment ◽  
Damage Index ◽  
Local Buckling ◽  
Local Stress ◽  
Local Strain ◽  
Physical Factor ◽  
Structural Members ◽  
Steel Members ◽  
Steel Angle ◽  
Cycle Loading

This study deals with damage processes to steel structural members up to an ultimate cracking state caused by local buckling that occurs under large deformations due to very-low-cycle loading. In this study, a very-low-cycle loading means a repetitive loading, with 5 to 20 loading cycles, within the large plastic range. Experiments were conducted on steel angle members that were subjected to very-low-cycle loading that caused global and (or) local buckling and plastic elongation. The objective of the experiments was to quantify important physical factor relationships between cracks and ruptures to large repetitive deformations. A nonlinear finite element method analysis was performed to trace the experimental behavior of steel structural members. A new approach to seismic damage assessment for steel members is proposed based on local stress-strain histories and cumulative states of deformation at critical parts.Key words: damage index, very-low-cycle loading, local strain, buckling, crack, steel member.

Experimental Research and Finite Element Analysis of Concrete-Filled Steel Box Columns with Longitudinal Stiffeners

2011 ◽  
Vol 287-290 ◽  
pp. 1037-1042 ◽  
Author(s):  
Jun Guang Zhang ◽  
Yong Jian Liu ◽  
Jian Yang ◽  
Kai Lei Xu
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Plates ◽  
Thin Wall ◽  
Test Results ◽  
Element Analysis ◽  
Longitudinal Stiffeners ◽  
Box Columns

For further study of mechanical properties of concrete-filled steel box columns (CFSBCs) with longitudinal stiffeners, axially loading tests of CFSBCs with longitudinal stiffeners was conducted to obtain their ultimate bearing capacity and failure modes. The test results were compared with those of hollow steel box columns with longitudinal stiffeners. Cross section of the test specimen was scaled from a chord member of Dongjiang Bridge. The experimental results show that failure mode of CFSBCs with longitudinal stiffeners is local buckling of steel plates, which is different from that of concrete-filled thin wall steel tube columns with longitudinal stiffeners. Although longitudinal stiffeners can prevent global buckling of steel plates, the effect is less obvious than that of concrete-filled thin wall steel tube columns. Meanwhile, three-dimensional finite element models (FEM) of the specimens were modeled using computer program ANSYS to obtain bearing capacities and load-strain curves. The FEM results coincide quite well with the test results. Further, influence of width to thickness ratio on mechanical behavior of CFSBCs was analyzed using FEM.

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